Theoretical studies on the basic processes of Si thermal oxidation.

硅热氧化基本过程的理论研究。

基本信息

批准号：
14550020
负责人：
SHIRAISHI Kenji
金额：
$ 2.18万
依托单位：
Institute of Physics, University of Tsukuba
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

In this research project, we have intensively studied the atomistic process in SiO_2 and at Si/SiO_2 interfaces, by using first principles calculations, macroscopic simulations and secondary ion mass spectroscopy (SIMS) experiments. We have investigated the effect of Si/SiO_2 interface reactions to impurity diffusion and Si self-diffusion in and at Si/SiO_2 interfaces by first principles calculations and by simultaneous diffusion equations. As a result, we have obtained the following remarkable results.(1) We investigated the diffusion mechanisms of boron in SiO_2. We find that a B atom forms various stable and meta-stable geometries in SiO_2 with point defects, depending on its charge state and surrounding environments. In the case of B in SiO_2 with an O interstitial, a B atom forms a very stable B-O complex in which the B atom is bound to the O interstitial. We also found that B atoms diffuse from Si substrates into SiO_2 layers under the existence of O species. Once the B-O complex … More is formed, the B atom diffuses via the SiO_2 network keeping this B-O unit with unexpectedly small activation energies of 2.1-2.3 eV that well reproduce experiments. Moreover, B-O complex can be regarded as the complex of B_<Si>-Si-O complex, since it is believed that B atoms substitute Si atoms in SiO_2. Accordingly, B diffusion are expected to be promoted by the existence of SiO. Since it has been reported that SiO content is high near Si/SiO_2 interfaces, our results imply that B diffusion will be promoted near Si/SiO_2 interfaces. These results are intimately related to the following SIMS experiments that high Si self-diffusivity is observed near Si/SiO_2 interfaces.(2) Simultaneous diffusion of Si in thermally grown SiO_2 is modeled taking into account the effect of SiO molecules generated at the Si/SiO_2 interface and diffusing into SiO_2 to enhance both Si diffusion. Based on the model, we simulated experimental SIMS profiles of co-implanted ^<30>Si in ^<28>SiO_2, which show high diffusivities near the interface that is supposed to have high SiO content. The experimental results were simulated by simultaneous diffusion equations, assuming that the diffusivity of SiO, which enhances the diffusivities of Si. The present result indicates that Si atoms in SiO_2 diffuse correlatively via SiO generated at Si/SiO_2 interfaces. Less

在该研究项目中，我们通过使用第一原理计算，宏观模拟和二级离子质谱（SIMS）实验，深入研究了SIO_2和SIO/SIO_2接口中的原子过程。我们已经通过第一原理计算和简单的扩散方程来研究了Si/SiO_2接口反应对Si/SiO_2接口中杂质扩散和SI自扩散的影响。结果，我们获得了以下显着的结果。（1）我们研究了硼在SIO_2中的扩散机制。我们发现，B原子在SIO_2中形成各种稳定和元稳定的几何形状，并具有点缺陷，具体取决于其电荷状态和周围环境。在SIO_2中使用O间隙中的B中，A B原子形成非常稳定的B-O复合物，其中B原子与O间隙结合。我们还发现，在O种的存在下，B原子从Si底物扩散到SIO_2层。一旦形成了B-O复合物……将通过SIO_2网络扩散B原子，使该B-O单元具有出乎意料的小激活能量为2.1-2.3 eV，良好地重现了实验。此外，B-O复合物可以被视为B_ <si> -Si-O复合物的复合物，因为据信B原子在SIO_2中替代Si原子。彼此之间，预计B扩散将通过SIO的存在来促进。由于据报道SIO含量在SI/SIO_2接口附近很高，因此我们的结果表明B扩散将在SI/SIO_2接口附近促进。这些结果与以下SIMS实验密切相关，即在SI/SIO_2接口附近观察到很高的Si自扩散性。（2）在SIO/SIO_2界面和Sio__2 diffor sio diff of sio sio分子的效果下，对SiO分子的热生长SIO_2的同时扩散是建模的SIO_2。基于该模型，我们模拟了 ^<28> sio_2中共植入 ^<30> si的实验模拟曲线，这些sio_2在界面附近显示出很高的差异，预计具有较高的SIO含量。假设SIO的扩散率增强了Si的扩散率，则通过同时扩散方程模拟实验结果。目前的结果表明SIO_2中的Si原子通过在Si/SiO_2接口处生成的SIO正确分散。较少的